title: Mechanical strain at alveolar bone and circummaxillary sutures during acute rapid palatal expansion.
abstract: BACKGROUND
  Palatal expansion can potentially affect alveolar bone and circummaxillary sutures. In this study, we characterized their mechanical strain during acute expansion.
  
  
  METHODS
  Eight 3- and 6-month-old fresh pig heads received acute palatal expansion with hyrax expanders. Strain gauges were used to measure strain at the buccal alveolar bone of anchor and adjacent nonanchor teeth, and at maxillary-premaxillary, maxillary-zygomatic, and zygomatic-temporal sutures during expansion. Intermolar width changes were measured from dental casts.
  
  
  RESULTS
  Intermolar width increased less than expander activation, and the midpalatal sutures were only opened slightly. Alveolar bone strain increased linearly with expander activation and decayed by 20% to 30% during postactivation intervals. Compressive strain at anchor-tooth alveolar bone locations was directed occlusally and apically, related to tooth tipping, and significantly higher than that at nonanchor tooth locations. With expander activation, suture strains increased monotonically and tended to plateau. Suture strain magnitude was generally similar to physiologic (masticatory) strains reported in the literature. The dominant strain polarity was compression at the maxillary-zygomatic and zygomatic-temporal sutures, but there was tension at the maxillary-premaxillary suture.
  
  
  CONCLUSIONS
  In these pigs, palatal expansion can cause significant occlusal-apical compression at buccal alveolar bone and physiologic-level strains at circummaxillary sutures.
authors.affiliation: Division of Orthodontics, College of Dentistry, Ohio State University, Columbus, Ohio, USA. sun.254@osu.edu
authors.forename: Zongyang
authors.initials: Z
authors.lastname: Sun
authors.forename: Sarah
authors.initials: S
authors.lastname: Hueni
authors.forename: Boon Ching
authors.initials: BC
authors.lastname: Tee
authors.forename: Hyeonseon
authors.initials: H
authors.lastname: Kim
mesh_terms: D000539:Alveolar Process / Q000502:physiology*; D000818:Animals; D001696:Biomechanical Phenomena; D001732:Bite Force; D003393:Cranial Sutures / Q000502:physiology*; D003724:Dental Arch / Q000033:anatomy & histology; D003799:Dental Stress Analysis / Q000295:instrumentation; D008437:Maxilla / Q000033:anatomy & histology / Q000502:physiology*; D023421:Models, Animal; D008963:Molar / Q000033:anatomy & histology; D010155:Palatal Expansion Technique / Q000295:instrumentation; D010159:Palate / Q000502:physiology; D013314:Stress, Mechanical; D034421:Sus scrofa; D013701:Temporal Bone / Q000502:physiology; D013997:Time Factors; D014070:Tooth / Q000502:physiology; D015050:Zygoma / Q000502:physiology